Thankyou for showing actual PID relation between RPM and the MAF. So many do a bad job of demonstrating these basics. Im going to have a look at your videos to see if you have a good one on how to use the MAF and fuel trim data to confirm vacuum leaks.
To diag a MAF all you need to do is monitor the MAF data stream on a scam tool. An engine will draw in a certain amount of air per engine size. To diag look at the data stream for the MAF sensor with the engine at idle. Data is read in grams per second. A 3.0 liter engine MAF sensor should report at least 3.0 grams per second at idle. If the reading is higher than 3.0 grams per second your MAF sensor is fine. If it's below the spec inspect your engines Intake system for leaks. Look at the air filter condition. Inspect for exhaust leaks ahead of the first O2 sensor. If all is well no leaks and the sensor still reads below 1 gram per second for each liter of engine size, remove the sensor and inspect for dirt or contamination on the hot wire in the sensor. Clean it with MAF sensor spray cleaner and retest. If the readings are still below normal recheck your previous work for vacuum and exhaust leaks and if all is well replaced the sensor I have fixed many many other techs comebacks after they replaced a MAF sensor but didn't verify engine integrity. Usually it's a vacuum leaks in the intake stream or an exhaust leak at the manifold doughnut gaskets. Retired after 40 years as a GM tech. It amazes me how many people don't bother to read or understand the proper diagnosis in auto repair.
Faulty MAF sensors can read correctly at idle. They need to be checked at other RPMs to verify if they can correctly report on airflow at all times. Checking just at idle is a very poor test and shows very little.
I think I found my issue, my MAF is reading under 2 g/s I think thats why I have system too lean and i did smoke test but nothing, STFT at 32% LTFT at 25% Thank you, waiting for my MAF hope this the culprit
Next time please also show the LT/ST fuel trims. That 4.8 g/s at idle on a 5.4L did seem a bit low. Would like to have seen if fuel trims were correcting for it. IME g/s is typically ~ (1.1 x displacement) at hot idle. So for the 5.4L I'd expect the it to read closer to 6 g/s.
How reliable are the fuel consumption/mileage figures obtained from the ECU via the scanner? I get about 10 km/l from the scanner but around 6 km/l when dividing the odometer reading by the quantity of fuel purchased. Indicative of a tweaked petrol pump dispenser or faulty scanner calculations or a bit of both???
My sensor seems to be working fine so what else could be affecting my mileage? I have a 2020 Camry xse and all of a sudden the mileage went from 25mpg to 15mpg my sensor is clean it’s plugged right and seems to be working fine
Actual specs for my engine: 2.6 - 3.7 g/s at warm idle (result: 4.0 to 4.2) 9.2 - 13.3 g/s held at 2,500 rpm warm (result: 12.2) It's a new MAF sensor and the grams per second are higher at idle than spec. Is that a bad thing?
2000 Ford 3.8 gas engine has a intermittent skip/stutter/hesitation/hiccup it is very rare and hard to catch. Only code is a P1100 (MAF) circuit intermittent fault. When recording live data for the MAF and TPS I have finally caught a spike but it is on the TPS from 17.6% to around 34.5% without the physical gas pedal being moved any and it is super short term like less than a second, curious part is that this spike does seem to coincide with the "skip/stutter/hesitation/hiccup" I originally suspected the MAF sensor since I had a P1100 code but could the MAF make the TPS have a spike reading and cause the hesitation? Or is it the other way around and the TPS sensor is bad causing the MAF circuit to reset and causing the P1100 circuit intermittent code? Sigh I guess it no one knows then I will just replace both and just move on.....
I found that at idle the mas airflow is lower than rpm (5.2 grams a second and it’s a 5.7 liter. Also noticed that when I increase rpm’s to 1900 it increases the grams per second 9 times when iam only going 3 in a half times the rpm as idle. Would this be a faulty or dirty maf?
Hello, I have a 2 litre diesel turbo engine. It reads around 12 g/s at idle. I have also tested a similar model, but it was a petrol and this read around 3 g/s at idle (6-700RPM). No engine codes, just feels sluggish when accelerating etc. Does this sound right or not?
For a petrol engine to idle, the airflow through it has to be restricted. This is done with a butterfly flap positioned in the air intake to the engine. The butterfly opens as you press the accelerator pedal. The further you push the pedal, the more it opens. At idle the butterfly is almost closed which significantly reduces airflow.. Diesel engines usually have an open airway and the revs are controlled by the amount of fuel injected and when. So, I would expect a diesel engine MAF to read much higher than on a petrol engine at idle
If the MAF goes up at idle with no foot on pedal and RPMs go up at the same time what is the problem? The MAF sensor reading the wrong amount of air or the IAC valve is opening more to let more air in? Can I blame the MAF for the increase in RPMs or is it the engine just increased the IAC valve opening for whatever reason? It is classic chicken or the egg scenario
Hello sir I'm new to this I have ford f-150 5.0L 2013 it hesitates an shows code for mass air flow sensor P0113 circuit high input an IAT P0102 circuit low input an on scan tool mass air flow sensor reading is 2.36 -2.36 no changes Any help is highly appreciated
Thank you for the video! My MAF reading is good at idle, but the ratio to rpm’s is lower than it should be at higher rpm’s. Could that possibly be a vac leak though?? Does that absolutely mean my maf isn’t working properly?
@@hunterautomotive4842 Thank you for the response. I changed the MAF sensor with one from autozone that they said works. It reads the same. I guess it has to be something else with the maf? I know for sure my b1 cat is not doing good. I thought the maf sensor may have been a cause or an effect.
My wife has a 18 highlander, I checked it the other day and it was reading 5-5.3g/s when it is a 3.5L v6. Should I be concerned about it? Short term fuel is 0.0 bank 1 and 5.5 long term bank one, and bank 2 is very similar.
Contaminated MAF sensors a lot of times will overreport the amount of air at idle and then underreport at the higher rpm’s. I would test it at 1000, 2000, and 3000 rpm’s.
@@hunterautomotive4842 thanks for the advice. Your videos are really insightful. Ive replaced an upstream oxygen sensor, will now replace the MAF. Got a P0171 ‘bank 1 system too lean’ code.
@@hunterautomotive4842 will give this a go, thanks for the advice. I had already changed the upstream oxygen sensor since getting a ‘P0171 - bank 1 system too lean’. It has returned since, i will now replace the MAF sensor.
Trying to factor in engine load would introduce a variable that's difficult to account for. That PID probably most useful to diag a misfire. Not so much for air/fuel testing.
very VERY helpful, short, sweet and to the point.
Thankyou for showing actual PID relation between RPM and the MAF. So many do a bad job of demonstrating these basics. Im going to have a look at your videos to see if you have a good one on how to use the MAF and fuel trim data to confirm vacuum leaks.
Just make a smoke machine and you can usually spot them a mile off
Man, your auto knowledges are awesome.. Salute 🥳🥳
Thank u young man never stop learning and improving yourself
To diag a MAF all you need to do is monitor the MAF data stream on a scam tool. An engine will draw in a certain amount of air per engine size. To diag look at the data stream for the MAF sensor with the engine at idle. Data is read in grams per second. A 3.0 liter engine MAF sensor should report at least 3.0 grams per second at idle. If the reading is higher than 3.0 grams per second your MAF sensor is fine. If it's below the spec inspect your engines Intake system for leaks. Look at the air filter condition. Inspect for exhaust leaks ahead of the first O2 sensor. If all is well no leaks and the sensor still reads below 1 gram per second for each liter of engine size, remove the sensor and inspect for dirt or contamination on the hot wire in the sensor. Clean it with MAF sensor spray cleaner and retest. If the readings are still below normal recheck your previous work for vacuum and exhaust leaks and if all is well replaced the sensor
I have fixed many many other techs comebacks after they replaced a MAF sensor but didn't verify engine integrity. Usually it's a vacuum leaks in the intake stream or an exhaust leak at the manifold doughnut gaskets.
Retired after 40 years as a GM tech. It amazes me how many people don't bother to read or understand the proper diagnosis in auto repair.
Faulty MAF sensors can read correctly at idle. They need to be checked at other RPMs to verify if they can correctly report on airflow at all times. Checking just at idle is a very poor test and shows very little.
I think I found my issue, my MAF is reading under 2 g/s I think thats why I have system too lean and i did smoke test but nothing, STFT at 32% LTFT at 25% Thank you, waiting for my MAF hope this the culprit
Hi, replacing the MAF corrected the STFT and LTFT on your vehicle ? I'm having same problem with my car ( LTFT 39% STFT 25%).
Next time please also show the LT/ST fuel trims. That 4.8 g/s at idle on a 5.4L did seem a bit low. Would like to have seen if fuel trims were correcting for it.
IME g/s is typically ~ (1.1 x displacement) at hot idle. So for the 5.4L I'd expect the it to read closer to 6 g/s.
This a great video
How reliable are the fuel consumption/mileage figures obtained from the ECU via the scanner?
I get about 10 km/l from the scanner but around 6 km/l when dividing the odometer reading by the quantity of fuel purchased.
Indicative of a tweaked petrol pump dispenser or faulty scanner calculations or a bit of both???
Good information❤❤❤❤
My sensor seems to be working fine so what else could be affecting my mileage? I have a 2020 Camry xse and all of a sudden the mileage went from 25mpg to 15mpg my sensor is clean it’s plugged right and seems to be working fine
Actual specs for my engine:
2.6 - 3.7 g/s at warm idle
(result: 4.0 to 4.2)
9.2 - 13.3 g/s held at 2,500 rpm warm
(result: 12.2)
It's a new MAF sensor and the grams per second are higher at idle than spec. Is that a bad thing?
Does it make a difference if the a/c is on ? Mine is reading bad with a/c off and good with a/c on...
2000 Ford 3.8 gas engine has a intermittent skip/stutter/hesitation/hiccup it is very rare and hard to catch. Only code is a P1100 (MAF) circuit intermittent fault. When recording live data for the MAF and TPS I have finally caught a spike but it is on the TPS from 17.6% to around 34.5% without the physical gas pedal being moved any and it is super short term like less than a second, curious part is that this spike does seem to coincide with the "skip/stutter/hesitation/hiccup" I originally suspected the MAF sensor since I had a P1100 code but could the MAF make the TPS have a spike reading and cause the hesitation? Or is it the other way around and the TPS sensor is bad causing the MAF circuit to reset and causing the P1100 circuit intermittent code? Sigh I guess it no one knows then I will just replace both and just move on.....
I found that at idle the mas airflow is lower than rpm (5.2 grams a second and it’s a 5.7 liter. Also noticed that when I increase rpm’s to 1900 it increases the grams per second 9 times when iam only going 3 in a half times the rpm as idle. Would this be a faulty or dirty maf?
my car is now 1.85, it used to be 1.45, when the air flowmeter is installed, it knocks when I give gas, it goes away when I pull the socket
You are awesome
Hello, I have a 2 litre diesel turbo engine. It reads around 12 g/s at idle. I have also tested a similar model, but it was a petrol and this read around 3 g/s at idle (6-700RPM). No engine codes, just feels sluggish when accelerating etc. Does this sound right or not?
For a petrol engine to idle, the airflow through it has to be restricted. This is done with a butterfly flap positioned in the air intake to the engine. The butterfly opens as you press the accelerator pedal. The further you push the pedal, the more it opens. At idle the butterfly is almost closed which significantly reduces airflow..
Diesel engines usually have an open airway and the revs are controlled by the amount of fuel injected and when. So, I would expect a diesel engine MAF to read much higher than on a petrol engine at idle
If the MAF goes up at idle with no foot on pedal and RPMs go up at the same time what is the problem? The MAF sensor reading the wrong amount of air or the IAC valve is opening more to let more air in? Can I blame the MAF for the increase in RPMs or is it the engine just increased the IAC valve opening for whatever reason? It is classic chicken or the egg scenario
At 2500rpm maf shows 5.92 g/s something seems wrong with my vehicles maf correct?
Hi i have a 2.0 diesel so should my gms be around 2 at idle thanks
What if it just shows in kpa?
Best vedio
Hello sir I'm new to this I have ford f-150 5.0L 2013 it hesitates an shows code for mass air flow sensor P0113 circuit high input an IAT P0102 circuit low input an on scan tool mass air flow sensor reading is 2.36 -2.36 no changes Any help is highly appreciated
Thank you for the video! My MAF reading is good at idle, but the ratio to rpm’s is lower than it should be at higher rpm’s. Could that possibly be a vac leak though?? Does that absolutely mean my maf isn’t working properly?
If the MAF and rpm are not tracking than it is the MAF that is bad
@@hunterautomotive4842 Thank you for the response. I changed the MAF sensor with one from autozone that they said works. It reads the same. I guess it has to be something else with the maf? I know for sure my b1 cat is not doing good. I thought the maf sensor may have been a cause or an effect.
Thank you for your video. On my 2006 Corolla 1.6 petrol, I read 3g/s at idle and 27g/s at 2600 rpm. Is it ok or is too high? Thank you!
Yeah that is way too high according to this video.
Mine shows 2.3 on idle? I got toyota matrix
My wife has a 18 highlander, I checked it the other day and it was reading 5-5.3g/s when it is a 3.5L v6. Should I be concerned about it? Short term fuel is 0.0 bank 1 and 5.5 long term bank one, and bank 2 is very similar.
That’s mean is good no lean no rich 👏🏽
Could it not be just a dirty air filter
My prius 1.8 litre petrol is giving at idle about 19kg/hour converted to 5.2g/s. This is too much air? What could cause this
Contaminated MAF sensors a lot of times will overreport the amount of air at idle and then underreport at the higher rpm’s. I would test it at 1000, 2000, and 3000 rpm’s.
@@hunterautomotive4842 thanks for the advice. Your videos are really insightful. Ive replaced an upstream oxygen sensor, will now replace the MAF. Got a P0171 ‘bank 1 system too lean’ code.
@@hunterautomotive4842 will give this a go, thanks for the advice. I had already changed the upstream oxygen sensor since getting a ‘P0171 - bank 1 system too lean’. It has returned since, i will now replace the MAF sensor.
Mine has no readings! Stays at 0.01
What about Load_pct(%)
Trying to factor in engine load would introduce a variable that's difficult to account for.
That PID probably most useful to diag a misfire. Not so much for air/fuel testing.